DTC Troubleshooting: P2648 (21)
DTC P2648:
 Rocker Arm Oil Control Solenoid Circuit Low Voltage
NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
  1. Turn the ignition switch ON (II).
  1. Clear the DTC with the HDS.
  1. Do the VTEC TEST in the INSPECTION MENU with the HDS.
Is the result OK?
YES -
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the rocker arm oil control solenoid and the ECM.■
NO -
Go to Step 4 .
  1. Turn the ignition switch OFF.
  1. Disconnect the rocker arm oil control solenoid 2P connector.
  1. At the solenoid side, measure resistance between rocker arm oil control solenoid 2P connector terminals No. 1 and No. 2.
Is there 14−30 Ω at room temperature?
YES -
Go to Step 7 .
NO -
Go to Step 10 .
  1. Jump the SCS line with the HDS.
  1. Disconnect ECM connector B (44P).
  1. Check for continuity between ECM connector terminal B34 and body ground.
Is there continuity?
YES -
Repair short in the wire between the ECM (B34) and the rocker arm oil control solenoid, then go to Step 11 .
NO -
Go to Step 18 .
  1. Reconnect all connectors.
  1. Turn the ignition switch ON (II).
  1. Reset the ECM with the HDS.
  1. Do the VTEC TEST in the INSPECTION MENU with the HDS.
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P2648 indicated?
YES -
Check for poor connections or loose terminals at the rocker arm oil control solenoid and the ECM, then go to Step 1 .
NO -
Go to Step 17 .
  1. Monitor the OBD STATUS for DTC P2648 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES -
Troubleshooting is complete. If any other Temporary DTCs or DTCs were indicated in Step 16 , go to the indicated DTC's troubleshooting.■
NO -
If the screen indicates FAILED, go to Step 1 and recheck. If the screen indicates NOT COMPLETED, go to Step 15 .
  1. Reconnect all connectors.
  1. Do the VTEC TEST in the INSPECTION MENU with the HDS.
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P2648 indicated?
YES -
Check for poor connections or loose terminals at the rocker arm oil control solenoid and the ECM. If the ECM was updated, substitute a known-good ECM, then go to Step 20 . If the ECM was substituted, go to Step 1 .
NO -
Go to Step 22 .
  1. Monitor the OBD STATUS for DTC P2648 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES -
If the ECM was updated, troubleshooting is complete. If the ECM was substituted, replace the original ECM. If any other Temporary DTCs or DTCs were indicated in Step 21 , go to the indicated DTC's troubleshooting.■
NO -
If the screen indicates FAILED, check for poor connections or loose terminals at the rocker arm oil control solenoid and the ECM. If the ECM was updated, substitute a known-good ECM, then go to Step 20 . If the ECM was substituted, go to Step 1 . If the screen indicates NOT COMPLETED, go to Step 20 .